Intermittent-flow condenser-storage timer



April 8, 1958 E. J. LEONARD 2,830,235

INTERMITTENT-FLOW coNDENsER-STORAGE TIMER Filed March 18, 1954 STARTPLsE W- a l CONTROL' l United. tetes Patnt INTERMITTENT-FLWCONDENSER-STRAGE 'TM/IER Edward J. Leonard, Chicago, 1li., assigner tolnternational Telephone and Telegraph Corporation, a corporation olMaryland Application March 18, 1954, Serial No. 417,109

12 Claims. (Cl. 317-141) This invention relates to an intermittent-dowcondenserstorage timer. lts principal obiect is to provide a newandimproved condenser-storage type of timer wherein the ilow of timingcurrent is intermittent, whereby the time required for the condenser topass the prearranged timing quantity of electricity is correspondinglyincreased.

A further object is to provide a condenser-storage timer of. theforegoing character in which the timing interval may be readily adjustedwithin fairly wide limits.

GENERAL DESCRIPTlON It has been chosen to illustrate this invention asapplied to relay apparatus suitable for use as a permanent timer commonto a number of trunk equipments on an automatic telephone switchboard.There, a permanent-timing interval of approximately two minutes, forexample, is commonly desired. Such an interval is considerably longerthan the time during which charging or discharging current ofrelay-operating or relay-holding value can be passed continuouslythrough a condenser of an economical capacity. According to theinventiointhis handicap is overcome by providing an associated pulsingarrangement wherein the timing condenser is required to passrelaycontrol current only at relatively momentary test intervals whichcorrespond respectively to the control pulses.

THE DRAWINGS Referring to the accompanying drawings, Figs. l, 2, and 3are respective schematic circuit diagrams of three embodiments of theinvention for supplying ground energization to output wires TH and TP,which may be the source of time-hold and time-pulse wires TH and TPshown in Fig. 5, part l of the drawings in the pending application' ofBellamy et al., Serial No. 85,292, r'iled April 4, i949, for a`Primary-Secondary-Spread Crossbar Telephone System.

In each embodiment the timer is controlled over the external pulse andstart leads P and ST, which are connected to their respective contactsPC and SC. The pulse contacts PC may be contacts of any well-knowninterrupter, and may deliver relatively short pulses at a fifteensecondinterval, for example. The start contacts SC may be contacts on a commonstart relay, which is arranged to be operated from any trunk equipmentin use.

DETAILED DESCRIPTION This invention having been described generally, adetailed description will now be given.

First embodiment (Fig. 1)

The timer of Fig. l includes tive electromagnetic relays of the typecommonly used on telephone switchboards. They comprise start, pulse, andtest relays 101 to 103, and control relays 104 and 105. Theserelays arecontrolled by current from the usual D. C. source, which has a groundedpositive pole and a free negative pole. Condenser 107 is the timingstorage condenser. It is normally maintained in a charged condition bybeing conice nected across the current source through limiting resistor110, and break contacts 2 of control relays 104 and 105, whereby it maybe of the type (electrolytic for example) which has a longer life whenmaintained charged at maximum potential difference when the circuit isquiescent. Otherwise, the grounded pole of the current source could besubstituted at the left-hand terminal of 107.

When timing is needed, start contacts SC close and remain closed untiltiming is no longer needed. Start relay 101 is operated by contacts SC,over start wire ST. At its contacts 1, relay 101 prepares an operatepath for the pulse relay 102; its contacts 3 prepare a hold circuit forcontrol relay 104 and an operate circuit for relay and its contacts 2operates test relay 103 by energizing its lower winding through closedcontacts 2 of pulse reiay 102. The timing operation now awaits pulsesover wire P.

Upon the receipt of the iirst ground pulse over wire P after theoperation of relay 101, relay 102 is operated through contacts 1 ofstart relay 101 for the duration of the pulse, perhaps fty milliseconds.At its contacts 1, relay 102 operates control relay 104 by energizingits lower winding over wire 111 through break contacts of breakmakecontact set 1 of relay 105. Ground applied to wire 111 shunts the lowerwinding of relay 105 (ground from wire 111 on one side of the windingand ground from wire 112 through closed contacts 3 of relay 104 on theother side) thereby preventing it from operating until ground is removedfrom wire 111. At its contacts 2, relay 104 opens the charging path forcondenser 107. At its contacts 2, relay 102 removes operating groundfrom the lower winding of test relay 103 and places a holding groundthereon through potentiometer 108. By varying the setting, ofpotentiometer 10S, the holding current for relay 103 may be varied. Atits contacts 3, relay 102. restores test relay 103 by energizing itsupper differential winding through its closed contacts 2.

The current ilow through the upper winding of test relay 103 causes areversal of magnetic tlux through its magnetic structure (not shown).This reversal of flux causes relay 103 to release in about tenmilliseconds, for example, opening its own restoring circuit at itscontacts 2. By varying the setting of potentiometer 109, therelay-control current drawn from timing-storage condenser 107 may bevaried.

At its contacts 1, relay 104 prepares its releasing circuit dependentupon when the relay-control current of condenser 107 diminishes therebyallowing relay 103 to remain operated during the receipt of la pulseover wire P; its contacts 2 opens the charging path of condenser 107;its contacts 3 closes its holding circuit and prepares an operatecircuit for relay 105; and its contacts 4 applies ground to output wiresTH and TP.

Upon the end of the iirst ground pulse over wire P, pulse relay 102restores. At its contacts 3, relay 102 opens the restoring circuit fortest relay 103; its contacts 1 removes ground potential from wire 111thereby removing the shunt from the lower winding of control relay 105at which time it operates in series with relay 104; its contacts 2reoperates test relay 103.

At its contacts 1, relay 105 prepares its hold circuit and also arelease circuitr for relay 104; its contacts 2 further opens thecharging path for condenser 107; and at its contacts 3 ground is removedfrom output wire TP and ground is applied to wire TH independent ofrelay 104.

Upon the receipt of the second ground pulse over wire P, relay 102 isagain reoperated placing the potentiometer 108 in the holding circuitfor relay 103 and completes the release path for the upper winding ofrelay 103 to restore it. Relays 104 and 105 remain operated beingconnected' in series from ground at contacts 3 of relay 101, contacts 3of relay 104, through their windings to battery. Relay 104 does notrestore when wire 111 is again grounded as it requires about thirtymilliseconds, for example, to restore. Before the period of timenecessary to release relay 104 has elapsed its release circuit is openedat contacts 1 of test relay 103 which restores in a shorter period oftime, perhaps ten milliseconds.

At the end of the second pulse over Wire P, relay 102 restores againreoperating test relay 103.

Upon the receipt of succeeding ground pulses over wire P, pulse relay102 is repeatedly reoperated and each cycle (operation and release)thereof, releases and reoperates test relay 103 in the manner asdescribed. The release operation of test relay 103 intermittently drawsrelay-control current from condenser 107, until such time (after thereceipt of a total of eight ground pulses over wire P, for example) thatthe condenser is discharged suiciently that the current is insuicient torestore test relay 103. At its contacts 1, relay 103 releases controlrelay 104 by energizing its upper differential winding from ground onwire 111, through contacts 1 of relays 105, 103 and 104.

Relay 104 upon releasing, at its contacts 2 prepares a charging circuitfor condenser 107, and at its contacts 4 places the ground on wire THunder control of relay 105. To prevent relay 104 from reoperation, itsholding and releasing circuits are opened at its contacts 3 and 1respectively.

At its contacts 1, relay 105 is held operated from ground on wire 111.

Upon the end of the ground pulse over wire P, pulse relay 102 restores.At its contacts 3, relay 102 removes condenser 107 from the restoringcircuit for test relay 103; at its contacts 2 relay 103 is reoperated;and at its contacts 1 ground is removed from wire 111 allowing relay 105to restore.

At its contacts 2, relay 105 reconnects condenser 107 across its currentsource to recharge it; and at its contacts 3 removes ground from wireTH.

If timing is no longer needed, the timer is returned to its normalcondition by opening start contacts SC, thereby allowing start relay 101and testrelay 103 to restore.

If there is any further need for timing, start contacts SC remain closedand the receipt of further ground pulses over wire P causes the timer tocontinually repeat its operational cycle until the start contacts SC areopened.

The timing interval may be readily adjusted by varying Second embodiment(Fig. 2)

The timer of Fig. 2 includes six electromagnetic relays, relays 201 to205 being similar to relays 101 to 105 of Fig. 1, and a slow-operatingdelay relay 206. Condenser 207 is normally maintained in a chargedcondition by being connected across the current source through limitingresistor 210, and break contacts 3 and 2 of control relays 204 and 205respectively.

When timing is needed, start relay 201 is operated in a manner asdescribed for start relay 101, of Fig. l. At its contacts 1, relay 201prepares an operate path for the pulse relay 202; and its contacts 2prepares a holding circuit for control relay 204 and an operate circuitfor control relay 205. The timing operation now awaits pulses over wireP.

Upon the receipt of the first ground pulse over wire P after theoperation of relay 201, relay 202 is operated through contacts 1 ofstart relay 201 for `the duration of the pulse. At its contacts 1, relay202 operates control 4' relay 204 by energizing its lower winding overwire 211 through break contacts of break-make contact set 1 of relay205.

At its contacts 1, relay 204 prepares its release circuit; its lcontacts2 prepares an operate circuit for test relay 203; its contacts 3 opensthe charging path for condenser 207; its contacts 4 closes its holdingcircuit and prepares an operate circuit for relay 205 from ground onwire 212; and its contacts 5 applies ground to output wires TH and TP.

Upon the end of the lirst pulse over wire P, pulse relay 202 restores.At its contacts 1, relay 202 removes ground from wire 211 allowing relay205 to operate in series with relay 204; and its contacts 3 operatestest relay 2.03 by energizing its lower winding through closed contacts2 of relay 204.

At its contacts 1, relay 205 prepares a release circuit for relay 204and its holding circuit; and its contacts 3 removes -ground from outputwire TP.

Upon the receipt of the second pulse over wire P, relay 202 isreoperated to release test relay 203 in the manner as described for testrelay 103, of Fig. l. Potentiometers 203 and 209 perform the samefunctions as potentiometers 10S and 109 of Fig. l. The release circuitfor relay 204 is not completed at this time because test relay 203 isreleased before delay relay 206 is operated. Relay 206 is provided withan upper short circuited winding to render it slow operating.

At the end of the second pulse over wire P, relay 202 restores toreoperate test relay 203.

Upon the receipt of succeeding pulses over wire P, relays 202, 203 and206 operate as described until the relay-control current of condenser207 is insuicient to release relay 203. The operation of slow-operatedelay relay 206 (when relay 203 remains operated during a pulse)completes the release circuit of relay 204 from ground on wire 211,contacts 1 of relays 206, 203, and 204.

At its contacts 3, relay 204 prepares a recharging circuit for condenser207; its contacts 1 opens its release circuit; its contacts 4 opens itsholding circuit and the Operate circuit for relay 205; its contacts 5places the ground on wire TH under control of relay 205; and itscontacts 2 releases test relay 203.

At its contacts 1, relay 205 is held operated for the duration of thepulse from ground on wire 211, through contacts 1 of delay relay 206.

At the end of the pulse, relay 202 restores removing holding ground fromwire 211 and releasing relay 206. Relay 205 releases completing thenoted charging circuit for condenser 207 and removes ground from wireTH.

As described for the timer of Fig. 1, if timing is no longer neededstart contacts ST are opened to release start relay 201; or if timing isfurther needed start contacts ST remain closed and the timer repeats itsoperational cycle until such time start contacts ST are opened.

Third embodiment (Fig. 3)

The timer of Fig. 3 includes six electromagnetic relays, relays 301 to305 being similar to relays 101 to 105 of Fig. l, and relays 201 to 205of Fig. 2, and a slow-release delay relay 306. Condenser 307 is normallymaintained in a charged condition by being connected across the currentsource through limiting resistor 310, break contacts 3 and 2 of relays304 and 305 respectively.

As described for Fig. 2, when timing is needed, start relay 301 isoperated to prepare operating circuits for relays 302 and 305 and aholding circuit for relay 304.

Upon the receipt of the first pulse over wire P after the operation ofstart relay 301, relay 302 is operated for the duration of the pulse. Atits contacts 1, relay 302 operates delay relay 306.

Relay 306 at its contacts 41V prepares an operate ycir-v cuit forcontrol relay 304.

At the end of the rst pulse, relay 302 releases to operate relay 304 byenergizing its lower winding through closed contacts 1 of slow-releaserelay 306 and contacts 1 of relay 105. l

Relay 306 has been provided with a copper sleeve over its magnetic coreto render it slow-releasing. Relay 306 will remain operated for fteenmilliseconds, for exam ple, after its operate circuit has been opened byrelay 302 thereby allowing relay 304 to operate and receive holdingground from wire 312 through its closed contacts 4 and the lower windingof relay 305.

At its contacts 1, relay 304 prepares its release circuit; its contacts3 opens the charging path forcondenser 307; its contacts 2 operates testrelay 303 by energizing its lower winding through contacts 2 of relays306 and 302; and its contacts applies ground to output wires TH and TP.

Relay 306 upon releasing allows relay 305 to operate in series withrelay 304 as described for relay 105 of Fig. 1. Relay 305 at itscontacts 3 removes ground from output wire TP.

Upon the receipt of the second pulse over wire P, relay 302 reoperatesto close the operating circuit for delay relay 306. At its contacts 2,relay 302 opens the operate circuit for relay 303 but is held operatedthrough potentiometer S.

At its contacts 1, relay 306 prepares a release circuit for relay 304;its contacts 2 further opens the operate path for relay 303; and itscontacts 3 releases relay 303 by energizing its upper-diilerentialwinding.

At the end of the second pulse over wire P, relay 302 releases and aftera slight delay relay 306 releases to reoperate test relay 303.

Upon the receipt of succeeding pulses over wire P, relays 302, 303, and306 operates, as hereinbefore described until the relay-control currentof condenser 207 is insufficient to release relay 303.

At the end of the pulse (when relay 303 remains operated during a pulse)relay 302 releases to restore control relay 304 by energizing itsupper-diterential winding through closed contacts 1 of relay 306, wire311, contacts 1 of relays 305, 303 and 304.

At its contacts 3, relay 304 prepares a recharging circuit for condenser207; its contacts 1 opens its release circuit, its contacts 4 opens itsholding circuit and the operate circuit for relay 305; its contacts 5places the ground on wire TH under control of relay 205; and itscontacts 2 opens the operate circuit for test relay 303.

At its contacts 1, relay 305 is held operated from ground on wire 311until delay relay 306 releases opening its holding circuit.

When relay 305 releases, it completes the recharging path for condenser307 and removes ground from wire TH.

As described for the timer of Fig. 1, if timing is no longer needed,start contacts ST are opened to release start relay 301; or if timing isfurther needed start contacts ST remain closed and the timer repeats itsoperational cycle until such time start contacts ST are opened.

Although the timers herein disclosed are shown as they may be applied inconjunction with permanent timing, it will be readily apparent to thoseskilled in the art that the provisions of the work contacts of thecontrol relays will readily lend themselves to numerous applications incircuit design.

I claim:

1. In an electric timer, a storage condenser, circuit means comprisingrst and second circuit paths for passing current through the condenserrespectively in irst and second directions, preparing means formaintaining the second path open and the tirst path closed to causecurrent ow in the iirst direction to bring the potential diierencebetween the terminals of the condenser to la preassigned starting value,starting means and means forrv operating it to start a timing period,means controlled by the starting means for disabling the preparing meansduring the started timing period, pulse means for closing the secondcircuit intermittently during the started timing period to cause currentto flow in the second direction to bring the potential differencebetween the condenser terminals to a preassigned termination value,whereby the current flow in the second circuit comprises. intermittentpulses lof a strength which diminishes progressively to a terminationvalue determined by the said termination value of potential difference,test means included in the second circuit, and means controlled by thetest means for terminating the started timing period responsive to apulse in the second circuit of a strength no greater than the saidtermination value of pulse strength.

2. In an electric timer according to claim l, said test means includinga relay having a test winding included in the second circuit, andcontacts on the test relay controlled by the ow of current through thetest winding for preventing termination of the started timing cycle solong as the pulses in the second circuit are of a greater strength thantheir said termination value.

3. in an electric timer according to claim 2, said test relay having asecond winding for controlling the relay contacts jointly with the rstwinding, and separate means for passing operatively effective currentthrough the second winding between closures of the second circuit.

4. in an electric timer according to claim 3, said relay windings beingopposed, with the second winding serving to operate the relay contactsand the first winding serving to restore them, said relay contactsincluding a pair which open the second circuit upon restoration by therst winding, whereby the second circuit is promptly openedto terminateany test pulse therein of greater than termination strength.

5. In an electric timer according to claim l, means included therein forholding the starting means operated and for maintaining the preparingmeans disabled throughout a timing period, the said means forterminating a timing period including means for restoring the startingmeans and for rendering the preparing means again effective.

6. In an electric timer according to claim 5, the pulse means forclosing the second circuit intermittently including means for deliveringa continuous succession of control pulses of which those deliveredduring a timing period are in timed relationship with respectiveclosures of the second circuits, the starting means, when restored,being responsive to any said control pulse, and means for delaying theoperation of the terminating means responsive to the termination closureof the second circuit until the associated control pulse is ended,whereby the resulting restoration of the starting means does not resultin the reoperation of the starting means until the next succeedingcontrol pulse is delivered.

7. ln an electric timer according to claim l, means for varying theimpedance of the second circuit to vary the cuinulated closure timerequired to reach an assigned termination value of potential differenceat the condenser terminals.

8. In an electric timer according to claim 1, means for varying thetermination value of current strength to vary the termination value ofpotential difference at the condenser terminals.

9. An electric timer comprising a storage condenser and means forcharging and discharging it in cycles each of which comprises a timingperiod and a recovery period, said charging and discharging meansincluding a pulse relay, a test relay, and control-relay mechanismhaving a recovery position and a timing position, pulse means foroperating the Ypulse relay intermittently at regular intervals whichdetermine the recovery period allowed, means responsive to an operationof the pulse relay for causing the control-relay apparatus to move fromrecovery position to timing,7 position to start tiniingrperiod whichincludes a plurality of the said intervals, means controlled by thepulse relay for closing a timing circuit for the test relay through thecondenser, the test relay responding to each such closure during thetiming period until the condenser is no longer able to furnish suicientcurrent, and means controlled by the test relay for causing thecontrol-relay apparatus to resume its recovery period until the pulserelay is next operated.

10. In an electric timer according to claim 9, a delay relay controlledby the pulse relay, and means controlled by the delay relayincluded inthe means for causing the control-relay apparatus to resume its recoveryposition.

11. In an electric timer according to claim 10, said delay relay being aslow-operating relay operated by the impulse relay.

12. In an electric timer according to claim l0, said delay relay being aslow-releasing relay operated by the impulse relay.

References Cited in the iile of this patent UNITED STATES PATENTS2,330,544 Bauer Sept. 28, 1943 2,339,581 Paulson Jan. 18, 1944 2,584,990Dimond Feb. l2, 1952 2,608,608 Handschin Aug. 26, 1952 2,699,507 SchnarzJan. 11, 1955

